In internal combustion engines a high compression ratio has a positive effect upon efficiency of the internal combustion engine. Compression ratio is generally referred to as a ratio of an entire cylinder volume before compression to a remaining cylinder volume after compression. In internal combustion engines with external ignition, for example gasoline engines which have a fixed compression ratio, the compression ratio however may only be selected up to a level so that a so called “knocking” of the internal combustion engine is avoided under full load operation. However, for much more prevalent partial load operation of the internal combustion engine, thus for a lower cylinder charge a combustion ratio with higher values can be selected without “knocking” occurring. The important partial load operation of the internal combustion engine can be improved when the compression ratio is variably adjustable. In order to adjust the compression ratio for example systems with a variable connecting rod length are known which actuate an eccentrical element adjustment device of a connecting rod using hydraulically or mechanically adjustable switch valves.
Connecting the connecting rod to a crank shaft of the internal combustion engine is performed through a crank bearing eye of the connecting rod, wherein a bearing shell is arranged between the crank bearing eye and a crank pin. A lubrication oil film can build up between the crank bearing eye and the crank pin.